The Visual Dictionary of Science & Energy

S C I E N C E &E N E R G YconductionHeat generation in a body (usually a solid) or between two bodies in contact; the molecules vibrate but no matter moves.convectionHeat generation in a fluid that is caused by a variation in temperature resulting from the movement of molecules. Here, the heated water expands, rises and releases its heat to the surrounding air.radiationHeat generation in the form of electromagnetic waves emitted by a heated body (solid, liquid or gas).solidRigid body possessing mass, volume and a definite form; its atoms are linked to each other and are almost completely at rest.vaporGaseous state of water above its boiling point (water boils and is converted to vapor at 212°F or 100°C).flameIncandescent gas resulting from the combustion of a mixture of gas and air; it produces heat and light.convection currentMovement of fluid caused by a difference in density, which transfers heat. The heated water rises and is replaced by the cooler water from the surface.liquidMatter having a definite mass and volume but no shape; its atoms are relatively mobile in relation to each other.T H E V I S U A LDICTIO N A RY OF



QA INTERNATIONALSCIENCE & ENERGYJean-Claude CorbeilAriane Archambault

ACKNOWLEDGEMENTSOur deepest gratitude to the individuals, institutions, companies, and businesses that have provided us with the latest technicaldocumentation for use in preparing this dictionary.Arcand, Denys (motion picture director); International Association of Marine Aids to Navigation and Lighthouse Authority; Canadian PaymentsAssociation (Charlie Clarke); Canadian Bankers Association (Lise Provost); Automobiles Citroën; Automobiles Peugeot; Bank of Canada (LyseBrousseau); Royal Bank of Canada (Raymond Chouinard, Francine Morel, Carole Trottier); Barrett Xplore inc.; Bazarin, Christine; Library ofCanadian Parliament (Information Services); Bibliothèque nationale du Québec (Jean-François Palomino); Bluechip Kennels (Olga Gagne);Bombardier Aerospace; Bridgestone-Firestone; Brother (Canada); Canadian National; Casavant Frères ltée; C.O.J.O. ATHENS 2004 (InternationalMedia Service); Centre Eaton de Montréal; Centre national du costume (Recherche et diffusion); Cetacean Society International (William R.Rossiter); Chagnon, Daniel (architect D.E.S. - M.E.Q.); Cohen et Rubin Architectes (Maggy Cohen); Commission scolaire de Montréal (École St-Henri); Hudson Bay Company (Nunzia Iavarone, Ron Oyama); Corporation d'hébergement du Québec (Céline Drolet); National Theatre School ofCanada (Library); Élevage Le Grand Saphir (Stéphane Ayotte); Atomic Energy of Canada; Eurocopter; Famous Players; Fédération bancairefrançaise (Védi Hékiman); Fontaine, PierreHenry (biologist); Future Shop; Garaga; Groupe Jean Coutu; Hôpital du Sacré-Cœur de Montréal;Hôtel Inter-Continental; Hydro-Québec; I.P.I.Q. (Serge Bouchard); IGA Barcelo; International Entomological Society (Dr. Michael Geisthardt);Irisbus; Jérôme, Danielle (O.D.); La Poste (Colette Gouts); Le Groupe Canam Manac inc.; Lévesque, Georges (urgentologist); Lévesque, Robert(chief machinist); Manutan; Marriott SpringHill Suites; MATRA S.A.; Métro inc.; National Defence of Canada (Public Affairs); ministère de laDéfense, République Française; ministère de la Justice du Québec (Service de la gestion immobilière - Carol Sirois); ministère de l'Éducation duQuébec (Direction de l'équipement scolaire - Daniel Chagnon); Muse Productions (Annick Barbery); National Aeronautics and SpaceAdministration; National Oceanic and Atmospheric Administration; Nikon Canada inc.; Normand, Denis (telecommunications consultant); Officede la langue française du Québec (Chantal Robinson); Paul Demers & Fils inc.; Phillips (France); Pratt & Whitney Canada inc.; Prévost Car inc.;Radio Shack Canada ltée; Réno-Dépôt inc.; Robitaille, Jean-François (Department of Biology, Laurentian University); Rocking T Ranch andPoultry Farm (Pete and Justine Theer); RONA inc.; Sears Canada inc.; Public Works and Government Services Canada: Translation Bureau;Correctional Service Canada; Société d'Entomologie Africaine (Alain Drumont); Société des musées québécois (Michel Perron); Société Radio-Canada; Sony du Canada ltée; Sûreté du Québec; Théâtre du Nouveau Monde; Transport Canada (Julie Poirier); Urgences-Santé (Éric Berry); Villede Longueuil (Direction de la Police); Ville de Montréal (Service de la prévention des incendies); Vimont Lexus Toyota; Volvo Bus Corporation;Yamaha Motor Canada Ltd.Science & Energy was created and produced byQA International329 De la Commune West, 3 Floor rdMontreal (Quebec) H2Y 2E1 CanadaT 514.499.3000 F 514.499.3010www.qa-international.com© QA International 2009. All rights reserved.No part of this book may be reproduced or transmitted in any form or byany means, electronic or mechanical, including photocopying, recording,or by any information storage and retrieval sytem, without permission inwriting by QA International.ISBN 978-2-7644-0881-0Printed and bound in Singapore10 9 8 7 6 5 4 3 2 1 12 11 10 09www.qa-international.comVersion 3.5.1

E D I T O R I A L S T A F F Editor: Jacques FortinAuthors: Jean-Claude Corbeil andAriane ArchambaultEditorial Director: François FortinEditor-in-Chief: Anne RouleauGraphic Designer: Anne TremblayP R O D U C T I O NNathalie FréchetteJosée GagnonT E R M I N O L O G I C A L R E S E A R C HJean BeaumontCatherine BriandNathalie GuilloE N G L I S H D E F I N I T I O N SNancy ButchartRita CloghesyTom DonovanDiana HalfpennyJohn WoolfreyKathe RothI L L U S T R A T I O N SArtistic Direction: Jocelyn Gardner Jean-Yves AhernRielle LévesqueAlain LemireMélanie BoivinYan BohlerClaude ThiviergePascal BilodeauMichel RouleauAnouk NoëlCarl PelletierRaymond MartinL A Y O U TPascal GoyetteDanielle QuintyÉmilie CorriveauPreliminary layout: Émilie BellemareSonia CharetteD O C U M E N T A T I O NGilles VézinaKathleen WyndStéphane BatigneSylvain RobichaudJessie DaigleD A T A M A N A G E M E N TProgrammer: Éric GagnonJosée GagnonR E V I S I O NVeronica Schami Jo HowardMarie-Nicole CimonLiliane MichaudP R E P R E S SKarine LévesqueFrançois HénaultJulien BriseboisPatrick MercureC O N T R I B U T I O N SQA International wishes to extend a special thank you to the following people for their contribution to this book:Jean-Louis Martin, Marc Lalumière, Jacques Perrault, Stéphane Roy, Alice Comtois, Michel Blais, Christiane Beauregard, Mamadou Togola,Annie Maurice, Charles Campeau, Mivil Deschênes, Jonathan Jacques, Martin Lortie, Frédérick Simard, Yan Tremblay, Mathieu Blouin,Sébastien Dallaire, Hoang Khanh Le, Martin Desrosiers, Nicolas Oroc, François Escalmel, Danièle Lemay, Pierre Savoie, Benoît Bourdeau,Marie-Andrée Lemieux, Caroline Soucy, Yves Chabot, Anne-Marie Ouellette, Anne-Marie Villeneuve, Anne-Marie Brault, Nancy Lepage,Daniel Provost, François Vézina, Guylaine Houle, Daniel Beaulieu, Sophie Pellerin, Tony O'Riley, Mac Thien Nguyen Hoang, Serge D'Amico.

IVEDITORIAL POLICYThe Visual Dictionarytakes an inventory of the physicalenvironment of a person who is part of today's technological ageand who knows and uses a large number of specialized terms in awide variety of fields.Designed for the general public, it responds to the needs ofanyone seeking the precise, correct terms for a wide range ofpersonal or professional reasons: finding an unknown term,checking the meaning of a word, translation, advertising, teachingmaterial, etc.The target user has guided the choice of contents for The VisualDictionary, which aims to bring together in 12 thematic books thetechnical terms required to express the contemporary world, in thespecialized fields that shape our daily experience.STRUCTUREEach tome has three sections: the preliminary pages, including thetable of contents; the body of the text (i.e. the detailed treatmentof the theme); the index.Information is presented moving from the most abstract to themost concrete: sub-theme, title, subtitle, illustration, terminology.TERMINOLOGYEach word in The Visual Dictionaryhas been carefully selectedfollowing examination of high-quality documentation, at therequired level of specialization.There may be cases where different terms are used to name thesame item. In such instances, the word most frequently used bythe most highly regarded authors has been chosen.Words are usually referred to in the singular, even if the illustrationshows a number of individual examples. The word designates theconcept, not the actual illustration.DEFINITIONSWithin the hierarchical format of The Visual Dictionary'spresentation, the definitions fit together like a Russian doll. Forexample, the information within the definition for the term insectat the top of the page does not have to be repeated for each of theinsects illustrated. Instead, the text concentrates on defining thedistinguishing characteristics of each insect (the louseis aparasite, the female yellow jacketstings, and so forth). Since the definition leaves out what is obvious from theillustration, the illustrations and definitions complement oneanother.The vast majority of the terms in the Visual Dictionaryare defined.Terms are not defined when the illustration makes the meaningabsolutely clear, or when the illustration suggests the usualmeaning of the word (for example, the numerous handles).METHODS OF CONSULTATIONUsers may gain access to the contents of The Visual Dictionaryina variety of ways:• From the TABLE OF CONTENTS at the end of the preliminarypages, the user can locate by title the section that is of interest.• With the INDEX, the user can consult The Visual Dictionaryfroma word, so as to see what it corresponds to, or to verify accuracyby examining the illustration that depicts it.• The most original aspect of The Visual Dictionaryis the fact thatthe illustrations enable the user to find a word even if he or sheonly has a vague idea of what it is. The dictionary is unique in thisfeature, as consultation of any other dictionary requires the userfirst to know the word.I N T R O D U C T I O N

98CHEMISTR YCHEMISTR YmatterAny substance that has mass, is composed of atoms and occupies space.matteratomFundamental unit of matter having unique chemicalproperties; it is composed of a nucleus and an electroncloud. One atom is distinguished from another by thenumber of protons in its nucleus.neutronConstituent particle of an atom’s nucleuswhose electric charge is neutral; it iscomposed of one u quark and two d quarks.nucleusCentral part of the atom whose electriccharge is positive; it is composed ofprotons and neutrons, around whichelectrons revolve.electronParticle having a negative electriccharge that revolves around thenucleus of the atom.protonConstituent particle of an atom’s nucleuswhose electric charge is positive; it iscomposed of two u quarks and one dquark.protonConstituent particle of an atom’s nucleuswhose electric charge is positive; it iscomposed of two u quarks and one d quark.d quarkThe d quark (down) is one of six typesof quarks (constituent particles ofprotons and neutrons) having anegative electric charge.moleculeMatter composed of atoms that constitutesthe smallest unit of a pure body that can existin a free state (e.g., water and carbondioxide).atomsAll matter in the universe is composedof approximately 100 types of atoms.chemical bondForce that unites two atoms through thesharing of a common electron (covalentbond) or the transfer of electrons (ionicbond) to form a molecule.u quarkThe u quark (up) is one of six types ofquarks (constituent particles of theprotons and neutrons) having apositive electric charge.solidRigid body possessing mass, volume and adefinite form; its atoms are linked to each otherand are almost completely at rest.condensationChange of a substance from a gaseousstate to a liquid state; it results fromcooling.liquidMatter having a definite mass andvolume but no shape; its atoms arerelatively mobile in relation to eachother.sublimationChange of a substance from a solid state directlyto a gaseous state without passing through theliquid state; it results from heating.freezingChange of a substance from a liquidstate to a solid state; it results fromcooling.meltingChange of a substance from a solidstate to a liquid state; it results fromheating.evaporationChange of a substance from a liquidstate to a gaseous state; it results fromheating.condensationChange of a substance from a gaseous stateto a liquid state; it results from cooling.crystallizationChange of a substance from anamorphous state to a crystallized state; itresults from cooling, which causes theatoms to become ordered.gasMalleable and expandable matterwhose only definable property is mass;its atoms are fully mobile with respectto each other.amorphous solidBody that resembles a congealedliquid whose atoms are not ordered.supercoolingThe process of cooling a liquid belowthe point at which it normally freezes(solidifies); its atoms becomeunstable.states of matterMatter exists in three fundamental states(solid, liquid and gaseous), which depend onthe temperature and pressure to which thematter is subjected.neutronConstituent particle of an atom’snucleus whose electric charge isneutral; it is composed of one u quarkand two d quarks.VILLUSTRATIONIt is an integral part of thevisual definition for each ofthe terms that refer to it.DEFINITIONIt explains the inherent qualities, function, orcharacteristics of the element depicted in theillustration.TITLEIts definition is found below. If the title refers toinformation that continues over several pages,after the first page it is shown in a shaded tonewith no definition.NARROW LINESThese link the word to the item indicated. Where too manylines would make reading difficult, they have been replacedby color codes with captions or, in rare cases, by numbers.SUB-THEMEThese are shown at the end of thepreliminary pages along with theirdefinitions. They are then repeated oneach page of a section, but without thedefinition.TERMEach term appears in the indexwith a reference to the pages onwhich it appears.

VICONTENTS52MEASURING DEVICES52 Measure of temperature55 Measure of time60 Measure of weight65 Measure of length65 Measure of distance66 Measure of thickness68 Measure of angles70SCIENTIFIC SYMBOLS70 International system of units72 Mathematics74 Biology75 Geometry76 Geometrical shapes82GEOTHERMAL AND FOSSIL ENERGY82 Production of electricity from geothermal energy84 Thermal energy86 Coal mine96 Oil112HYDROELECTRICITY112 Hydroelectric complex116 Generator unit119 Examples of dams124 Steps in production of electricity126 Electricity transmission130 Tidal power plant8CHEMISTRY8Matter12 Chemical elements21 Laboratory equipment24 Chemistry symbols25PHYSICS: MECHANICS24 Lever25 Gearing systems26 Double pulley system27PHYSICS: ELECTRICITY AND MAGNETISM27 Parallel electrical circuit28 Generators30 Dry cells32 Electronics34 Magnetism35PHYSICS: OPTICS35 Wave36 Electromagnetic spectrum37 Color synthesis38 Vision40 Lenses41 Pulsed ruby laser42 Prism binoculars43 Magnifying glass and microscopes48 Telescopic sight50 Reflecting telescope51 Refracting telescope

VII134NUCLEAR ENERGY134 Production of electricity from nuclear energy138 Fuel handling sequence140 Fuel bundle141 Nuclear reactor142 Nuclear generating station144 Carbon dioxide reactor146 Heavy-water reactor148 Pressurized-water reactor150 Boiling-water reactor152SOLAR ENERGY152 Solar cell153 Flat-plate solar collector154 Solar-cell system156 Solar furnace158 Production of electricity from solar energy160 Solar house163WIND ENERGY163 Windmill165 Wind turbines and electricity production169INDEX

8CHEMISTR YmatterAny substance that has mass, is composed of atoms and occupies space.atomFundamental unit of matter having unique chemicalproperties; it is composed of a nucleus and an electroncloud. One atom is distinguished from another by thenumber of protons in its nucleus.neutronConstituent particle of an atom’s nucleuswhose electric charge is neutral; it iscomposed of one u quark and two d quarks.nucleusCentral part of the atom whose electriccharge is positive; it is composed ofprotons and neutrons, around whichelectrons revolve.electronParticle having a negative electriccharge that revolves around thenucleus of the atom.protonConstituent particle of an atom’s nucleuswhose electric charge is positive; it iscomposed of two u quarks and one dquark.protonConstituent particle of an atom’s nucleuswhose electric charge is positive; it iscomposed of two u quarks and one d quark.d quarkThe d quark (down) is one of six typesof quarks (constituent particles ofprotons and neutrons) having anegative electric charge.moleculeMatter composed of atoms that constitutesthe smallest unit of a pure body that can existin a free state (e.g., water and carbondioxide).atomsAll matter in the universe is composedof approximately 100 types of atoms.chemical bondForce that unites two atoms through thesharing of a common electron (covalentbond) or the transfer of electrons (ionicbond) to form a molecule.u quarkThe u quark (up) is one of six types ofquarks (constituent particles of theprotons and neutrons) having apositive electric charge.neutronConstituent particle of an atom’snucleus whose electric charge isneutral; it is composed of one u quarkand two d quarks.

9CHEMISTR YmattersolidRigid body possessing mass, volume and adefinite form; its atoms are linked to each otherand are almost completely at rest.condensationChange of a substance from a gaseousstate to a liquid state; it results fromcooling.liquidMatter having a definite mass andvolume but no shape; its atoms arerelatively mobile in relation to eachother.sublimationChange of a substance from a solid state directlyto a gaseous state without passing through theliquid state; it results from heating.freezingChange of a substance from a liquidstate to a solid state; it results fromcooling.meltingChange of a substance from a solidstate to a liquid state; it results fromheating.evaporationChange of a substance from a liquidstate to a gaseous state; it results fromheating.condensationChange of a substance from a gaseous stateto a liquid state; it results from cooling.crystallizationChange of a substance from anamorphous state to a crystallized state; itresults from cooling, which causes theatoms to become ordered.gasMalleable and expandable matterwhose only definable property is mass;its atoms are fully mobile with respectto each other.amorphous solidBody that resembles a congealedliquid whose atoms are not ordered.supercoolingThe process of cooling a liquid belowthe point at which it normally freezes(solidifies); its atoms becomeunstable.states of matterMatter exists in three fundamental states(solid, liquid and gaseous), which depend onthe temperature and pressure to which thematter is subjected.

10incident neutronThe fission of a nucleus releases two orthree neutrons, which in turn bombardother nuclei and divide them.nucleus splittingWhen the atom’s nucleus is bombarded by a neutron, it absorbs itand becomes unstable; it then divides into two smaller nucleiusually of identical size.nuclear fissionProcess by which the atoms’ nuclei become fragmented(e.g., in a nuclear reactor); neutrons are released andenergy is produced in the form of heat.fission products (radioactive nuclei)The nuclei of unstable atoms produced by fission emitrays that can be harmful to living organisms.fissionable nucleusOnly heavy nuclei, such as those ofuranium and plutonium, can undergofission following a collision with aneutron.chain reactionDuring nuclear fission, parts of the atom’s nucleusthat have been broken off by collision with theneutron will in turn bombard other nuclei toproduce more fission.incident neutronA free neutron comes into collision with an atom’s nucleus,which it then splits.energy releaseNuclear fission is accompanied by a very largerelease of energy, which is derived from the forcesthat caused the nucleus’s cohesion.fissionable nucleusOnly heavy nuclei, such as those ofuranium and plutonium, can undergofission following a collision with aneutron.CHEMISTR Ymatter

liquidMatter having a definite mass andvolume but no shape; its atoms arerelatively mobile in relation to eachother.11convectionHeat generation in a fluid that is caused by a variation intemperature resulting from the movement of molecules. Here, theheated water expands, rises and releases its heat to thesurrounding air.heat transferHeat transfer occurs in three ways that arerelated to molecular movement: conduction,convection and radiation.vaporGaseous state of water above its boiling point (waterboils and is converted to vapor at 212°F or 100°C).conductionHeat generation in a body (usually a solid) or betweentwo bodies in contact; the molecules vibrate but nomatter moves.solidRigid body possessing mass, volume anda definite form; its atoms are linked to eachother and are almost completely at rest.flameIncandescent gas resulting from the combustion of a mixture ofgas and air; it produces heat and light.convection currentMovement of fluid caused by a difference indensity, which transfers heat. The heated waterrises and is replaced by the cooler water fromthe surface.radiationHeat generation in the form ofelectromagnetic waves emitted by aheated body (solid, liquid or gas).CHEMISTR Ymatter

12table of elementsTable created by Dmitry Mendeleyev in 1869 that classifies the now approximately 110 knownchemical elements such as oxygen, hydrogen, iron and lead. The elements are classified in order oftheir atomic weight and arranged into groups having similar properties.chemical elementsThere are more than 110 chemical elements, most of which are naturally present in the universe. The others arecreated artificially in the laboratory.atomic numberNumber that indicates the order of a chemical element in the table of elements and corresponds tothe number of protons contained in its nucleus.symbolThe name of each chemical element is represented by one or two letters, the first of which is inuppercase (e.g., O for oxygen, Cl for chlorine).CHEMISTR Y

13chemical elementsCHEMISTR YhydrogenThis gas is the most abundant element in the universe and makes up part of the composition of water. It is usedespecially in petrochemistry and rocket engines.

14lithiumThe lightest of all the metals is usedespecially in alloys for the aerospaceindustry, in household batteries and inmedicine.berylliumUncommon metal that is used especiallyin alloys for the aerospace industry andas a moderator in nuclear reactors.magnesiumMetal necessary for the growth andmetabolism of most living organisms;it is also a component of aluminumalloys.sodiumMetal that is used especially instreetlights, kitchen salt (sodiumchloride) and the manufacture of glassand cosmetic products.calciumMetal that is one of the most essentialelements in bones and teeth; it is also acomponent of cement, plaster and somealloys.potassiumVery reactant light metal that is usedespecially in fertilizer and matches; itssalts are used in medicine.rubidiumMetal similar to potassium but much rarerthat is used in the manufacture ofphotoelectric cells and special kinds ofglass and lasers.strontiumRelatively rare metal that is usedespecially in pyrotechnics (fireworks),the manufacture of magnets andmedicine.cesiumRare metal that is used especially inphotoelectric cells, atomic clocks,infrared lamps and treating certaincancers.bariumRelatively abundant metal that is usedespecially in lubricants, pyrotechnics(fireworks), paint and radiology.franciumThe heaviest of the alkali metals is veryrare and radioactive and has a very shortlife span (about 22 minutes).radiumExtremely radioactive metal present invery low quantities in uranium ore; it isused mainly in medicine as a cancertreatment.alkali metalsGenerally soft and silvery and very good conductors of heat and electricity; they are very reactant withnonmetals and break down in cold water.alkaline earth metalsGenerally silvery and malleable and good conductors of heat and electricity; they react easily withnonmetals and water.chemical elementsCHEMISTR Y

15boronSemimetal that is used especially as aneutron absorber in nuclear reactors, as arocket fuel and in detergents.aluminumLight metal that is used especially inaeronautics, cars, buildings, electriccables, kitchen utensils and packaging.siliconMost common element on the planet afteroxygen; it is used mostly in the manufactureof electronic devices because of itssemiconductor properties.galliumRare metal that is used especially in high-temperature thermometers,electroluminescent diodes and televisionscreens (the color green).germaniumRare semimetal that is used especially inthe manufacture of electronic devices andin optical equipment (camera andmicroscope lenses).arsenicToxic semimetal that is used especiallyin very low doses for therapeutic usesand in the manufacture ofsemiconductors.seleniumSemimetal that is usually used inphotoelectric cells and semiconductors; itis an indispensable trace element fororganisms.indiumVery rare metal that is used especially inrace car engines and electronic devices,and as a coating for glass.tinMetal that is used especially as ananticorrosive for copper and steel and as acomponent in the preparation of bronze,welding and toothpaste.antimonySemimetal that is used in several alloys(mostly with lead) and especially inmaking metal for printing type andsemiconductors.telluriumRare semimetal that is used especially inthe manufacture of detonators, electricresistors, rubber, ceramics and glass.thalliumMetal that is used especially in infrareddetectors and some kinds of glass.leadHeavy toxic metal that is used to preventcorrosion, as a protection against radiationand in accumulator batteries, paint andglass.bismuthRelatively rare metal that is usedespecially in alloys and cosmetics andin medicine (treatments for gastriculcers and diarrhea).poloniumVery rare radioactive metal that is usedas fuel in nuclear reactors; it emitsradiation that is much more powerfulthan that of uranium.other metalsThese elements are not part of any other category of metal; they are sometimes calledposttransition metals.semi-metals (metalloids)Nonmetallic elements that are lusterless and solid; they possess a certain amount of electricand thermal conductivity.chemical elementsCHEMISTR Y

16carbonElement common in its pure state (diamond,graphite) or found in combination (air, coal,petroleum); it is present in animal and planttissue.nitrogenGas that constitutes about 78% of theEarth’s atmosphere, present in all animaland vegetable tissue (proteins), and infertilizer, ammonia and explosives.oxygenGas that is the most abundant element onEarth and that comprises about 20% of theatmospheric air; it is used to breathe and inthe manufacture of steel.fluorineGas that is used especially for enrichinguranium and manufacturing antistickcoatings; it is present in bones and teeth.chlorineAbundant toxic gas that is used towhiten fabric and paper, disinfect waterand manufacture various other products(solvents).sulfurSolid that is quite common in nature; itis used in car batteries, fertilizer, paint,explosives, pharmaceuticals andrubber.phosphorusSolid used especially in fertilizer(phosphates), matches andpyrotechnics (fireworks); it is alsonecessary for human beings.bromineVery toxic liquid that is used mainly tomanufacture teargas, dyes anddisinfectants and in photography andmedications.iodineSolid that is used especially inpharmaceuticals (revulsives,antiseptics), in photography and dyes; itis also essential for the human body.astatineRadioactive element that is extremelyrare in nature; it is used in medicine tostudy the thyroid gland and to detectcancerous tumors.non-metalsNonmetallic elements that are lusterless and nonmalleable; they are mostly gases and solids and areusually poor conductors of heat and electricity.heliumThe lightest of the noble gases isnoncombustible and abundant in the stars;it is used especially in inflating aerostats(such as balloons and dirigibles).neonNoble gas that is used mainly in lighting(billboards, television tubes and foglamps), but also as a liquid coolant.argonMost abundant of the noble gases; it isused especially in incandescent lampsand in welding (protective gas).radonHighly radioactive noble gas that isused mainly in medicine (destroyingcancerous tumors) and in predictingearthquakes.noble gasesFamily of chemical elements also called inert, as they are weakly reactant.chemical elementsCHEMISTR YxenonRarest gas in the atmosphere; it is usedmainly in discharge lamps, photoflashbulbs and lasers.kryptonNoble gas that is used in someincandescent lamps and inphotography.

17chemical elementsCHEMISTR Ylanthanides (rare earth)Very reactant elements found in the lanthanide series (monazite, xenotime); some arerelatively abundant in the Earth’s crust.lanthanumMetal that reacts with water to yieldhydrogen; it is used especially in flintalloys and optical glass.europiumThe most reactant metal of the lanthanidegroup; it is used especially in televisionscreens (the color orange) and nuclearreactors (absorbing neutrons).gadoliniumMetal that is often alloyed with chromedsteel; it is used especially in themanufacture of permanent magnets,magnetic heads and electronic components.ceriumThe most common metal of thelanthanide group and the mainconstituent of flint alloys (misch metal).praseodymiumMetal that is used especially in protectivelenses, colorants for glass, flint alloys(misch metal) and permanent magnets.neodymiumOne of the most reactant of rare metals; itis used mainly to manufacture lasers,eyeglasses and permanent-magnetalloys.promethiumRadioactive metal that is used mainly inspecialized batteries and luminescentcoatings for watches, and as a source of X-rays in medicine.samariumRare radioactive metal that is usedespecially in optical glass, lasers,nuclear reactors (absorbing neutrons)and permanent magnets.terbiumRare metal that is used especially inlasers and semiconductors.holmiumVery rare metal with limitedapplications; it is used in lasers and forcoloring glass.dysprosiumVery rare metal that is used especially inpermanent magnets, lasers and nuclearreactors (absorbing neutrons).lutetiumVery rare metal that is difficult toseparate; it has no real industrialapplications but can be used as acatalyst (cracking, hydrogenation).thuliumThe rarest of the lanthanide group; it isused as a source of X-rays in portableradiology equipment and in themanufacture of ferrites (magneticceramics).ytterbiumMetal that is used in the manufacture ofstainless steel, in lasers and as asource of X-rays in portable radiologyequipment.erbiumMetal that is used mainly in somealloys (especially with vanadium),lasers and infrared-absorbing glass,and as a colorant for glass and enamel.

18chemical elementsCHEMISTR YscandiumRare and very light metal that is employed inaerospace construction because of its highfusion point (about 2,700°F or 1,500°C).titaniumMetal that is used in several alloysemployed in the manufacture of precisionitems and as a coating for light aerospaceparts.vanadiumMetal that is used mainly in alloys, to whichit provides highly anticorrosive properties.chromiumBright metal that is used as an anticorrosivecoating and in the manufacture of hard andresistant alloys; it gives emeralds and rubiestheir color.manganeseHard metal that is used mainly in themanufacture of specialty steels andhousehold batteries; it is also anindispensable trace element for humans.ironThe most used metal in the world due to itsvariety of alloys (steel, cast iron); it helpsmove oxygen through the body.cobaltStrong metal that is used in alloys(cutting tools, magnets) and inradiotherapy; it also yields a bluepigment.nickelHard metal that resists corrosion; it isused in the manufacture of coins andcutlery, and as a protective coating forother metals (iron, copper).copperReddish-brown metal that is a very goodconductor of heat and electricity; it isused mainly in the manufacture ofelectric wire and alloys (brass, bronze).zincRelatively abundant metal that isresistant to corrosion; it is usedespecially in the manufacture of alloys,tires, paint, ointments and perfume.yttriumRare metal used in the manufacture ofalloys, electronic components, lasers,television screens and in nuclearreactors.zirconiumMetal that is used in alloys for thenuclear industry (protective sheathing,fuel rods) and in jewelry (imitationdiamonds).niobiumRare metal that is used especially inalloys for jet aircraft, missiles,nuclear reactors, ointments andcutting tools.molybdenumHard metal that is used in alloys(aircraft, missiles, nuclear reactors),electric lights and electronic tubes.technetiumRadioactive metal (first element tohave been produced artificially) thatmakes steel corrosion-free and isused in medical imaging.rutheniumRare metal that hardens platinumand palladium; it is used in themanufacture of electric contacts,spark plugs and jewelry.rhodiumRare metal that resists corrosion andhardens platinum and palladium; itis used especially in catalyticconverters and jewelry.palladiumRare and precious metal that is usedespecially in dentistry (dentalprostheses), jewelry (white gold)and in catalytic converters.transition metalsUsually less reactant than alkali metals and alkaline earth metals but very good electric and thermalconductors. Many of these metals form vital alloys.

19cadmiumMetal that is used especially as aprotective covering for steel, inrechargeable batteries and in nuclearreactors (control rods).hafniumRare metal that is used in the controlrods of nuclear reactors, filaments forincandescent lamps and jet engines.osmiumRare metal often alloyed with iridiumand platinum; it is used in pen tips,bearings, compass needles and jewelry.iridiumRare metal that is often alloyed withplatinum; it is used especially inelectric contacts and jewelry.platinumVery rare metal used especially as acatalyst in chemistry (petrochemicals,vitamins), in jewelry and in precisionequipment.tantalumSomewhat rare metal that is highlyresistant to heat; it is used especially innuclear reactors, missiles andcapacitors.tungstenMetal that is resistant to very high heat; itis used in filaments for incandescentlamps and cutting tools.rheniumRare metal that is resistant to wear andcorrosion; it is used especially in pentips and incandescent filaments forovens.goldPrecious metal (nuggets, flakes) that isused as currency (ingots) and injewelry, dentistry and electronics.mercuryRare metal that is used in measuringinstruments (thermometers,barometers) and in the electricityindustry.rutherfordiumArtificial radioactive element that wasfirst produced in laboratories in the1960s; it has applications only inscientific research.dubniumArtificial radioactive element that wasfirst produced in laboratories in the1960s.seaborgiumArtificial radioactive element that wasfirst produced in laboratories in 1974;it is based on californium and oxygen.bohriumArtificial radioactive element that wasfirst produced in laboratories in 1976; itis based on bismuth and chromium.hassiumArtificial radioactive element that wasfirst produced in laboratories in 1984; itis based on lead and iron.meitneriumArtificial radioactive element that wasfirst produced in laboratories in 1982; itis based on bismuth and iron.darmstadtiumArtificial radioactive element that wasfirst produced in laboratories in 1994; itis based on nickel and lead.roentgeniumArtificial radioactive element that wasfirst produced in laboratories in 1994; itis based on bismuth and nickel.ununbiumArtificial radioactive element that wasfirst produced in laboratories in 1996; itis based on lead and zinc.chemical elementsCHEMISTR YsilverPrecious metal that is the best conductorof heat and electricity; it is usedespecially in the manufacture of mirrors,jewelry and coins.

20actinidesRadioactive elements that are abundant in nature (elements 89 to 92) or made artificially (elements93 to 103). Most of them have no industrial applications.actiniumMetal that is present in small quantitiesin uranium ore; it is used mainly as asource of neutrons in nuclear reactors.thoriumNatural metal that is used especially inalloys, photoelectric cells and uraniumproduction.protactiniumVery rare metal that is present inuranium ore; it has few applicationsoutside of scientific research.uraniumNaturally abundant metal that is usedmainly as fuel in nuclear reactors aswell as in nuclear weapons.neptuniumRare metal that is produced fromuranium; it is used in neutron-detection instruments.plutoniumMetal that is produced from uranium; itis used especially as fuel in nuclearreactors as well as in nuclear weapons.americiumMetal that is produced from plutonium;it is used mainly in smoke detectorsand in radiology.curiumMetal that is produced in smallamounts from plutonium; it is usedespecially in thermoelectric generatorsfor spacecraft propulsion.berkeliumMetal that is produced in smallamounts from americium; it is used forscientific research only.californiumMetal produced from curium that isused especially in the treatment ofcancer and in some measuringinstruments such as humidistats.einsteiniumMetal that was discovered in 1952among the debris of the firstthermonuclear explosion in the Pacific; itis used for scientific research only.fermiumMetal that was discovered at the sametime as einsteinium; it is used forscientific research only.mendeleviumMetal that is produced from einsteinium;it is named in honor of the chemistMendeleyev (who classified theelements).nobeliumMetal that is produced from curium; it isnamed in honor of Alfred Nobel (inventorof dynamite and founder of the NobelPrize).lawrenciumMetal that is produced from californium;it is used for scientific research only.chemical elementsCHEMISTR Y

21laboratory equipmentThese materials are highly varied: measurement instruments, various containers, heat sources, experimentationmaterials and mounting hardware.bottleContainer of various sizes and shapes andusually with a straight neck for holdingliquids.wash bottleFlexible container that is squeezed lightly tosquirt a liquid; it is used especially forcleaning equipment (test tubes, pipettes).round-bottom flaskSpherical container used mainly for boilingliquids.beakerGraduated container with a spout; it is usedto create reactions (precipitation,electrolysis) and to measure approximateamounts of liquid.Erlenmeyer flaskGraduated cone-shaped container that is used veryfrequently in laboratories; it can have a stopper and isused especially for mixing and measuring liquids.CHEMISTR Y

laboratory equipmentCHEMISTR Y22gas burnerDevice that is fueled by gas to producea flame for heating chemical products.clamp/holderPart attached to the stand’s rod by a holder andhaving tongs that clamp onto the laboratoryequipment to hold it in place.holderPart with a screw for attaching a clamp onto the stand’srod.rodLong metal part to which various laboratorydevices can be clamped.baseHeavy metal pedestal supporting the rod.standUnit consisting of a base and a rod; it supports variouslaboratory apparatuses such as burettes and flasks.

laboratory equipmentCHEMISTR Y23graduated cylinderGraduated tube with a spout that is usedespecially for measuring small amounts ofliquid with precision.test tubeCylindrical tube used to conduct variouschemical experiments on smallquantities (normally, it is not filled aboveone-third).straight stopcock buretteLong graduated tube for measuring liquids withhigh precision; it is fitted with a valve for manuallyregulating the flow.serological pipetteFine tube that is open at both ends; it isused to transfer very precise quantitiesof liquids from one container toanother.Petri dishFlat transparent box for culturingmicroorganisms; it has a cover to protect themfrom contamination.

24negative chargeSymbol that indicates a surplus of electrons in anatom, which means the atom has a negative electriccharge. The chlorine atom, for example, forms anegative ion that is denoted as Cl-.positive chargeSymbol that indicates a loss of electrons in an atom,which means the atom has a positive electric charge.The sodium atom, for example, forms a positive ionthat is denoted as Na+.reversible reactionChemical reaction that can occur in bothdirections; the products obtained (direct reaction)react between them to change back into theoriginal reactants (inverse reaction).reaction directionA chemical reaction corresponds to the conversion ofreactants in products and is obtained by the loss of one ofthe reactants. The arrow indicates the direction in whichthis irreversible reaction occurs.chemistry symbolsSymbols that simplify the writing of the elements, formulas and chemical reactions.CHEMISTR YfulcrumPoint around which the lever pivots.leverSystem consisting of a bar pivoting on a fulcrum to lift a load. The amount of effort required is related to theposition of the pivot and the length of the bar.pivotPart providing an efficient fulcrum forthe lever.effortForce exerted on the lever bar in orderto shift the load.loadWeight whose inertia exerts a forceopposite to the effort exerted on thebar.barRigid moving bar around the fulcrum on whichan effort is exerted to lift the load.

25rack and pinion gearGearing system converting a rotational movementinto a horizontal movement (and vice versa); it isoften used in the steering systems of automobiles.spur gearMost common gearing system linking two parallelshafts that changes the speed and force of a rotation; itis used especially in automobile transmissions.bevel gearGearing system linking two shafts at right angles that changesthe direction of rotation; it is used especially in car jacks.worm gearOne-way gearing system (only the screw can drive the wheel) forslowing down the speed of rotation between two perpendicular axles;it is used especially in the automobile industry (Torsen differential).toothed wheelWheel with teeth that mesh with the teethof another wheel to transmit rotationalmovement to it.shaftCylindrical part that transfers the rotational movement ofone part to another.gear toothProtrusion on the gear wheel; the teeth of onewheel enter the gaps of another wheel to form agearing system.PHYSICS: MECHANICSgearing systemsMechanisms consisting of toothed parts that mesh to transmit the rotational motion of the shafts they are a part of.

26double pulley systemSystem consisting of two pulleys with a rope running around them to lift a load. Using two or more pulleysreduces the amount of effort needed.effortForce exerted on the pulley’s rope to lift the load.ropeCord that slides on the pulley and ispulled to lift the load.pulleyDevice with a grooved wheel (sheave wheel) around which a rope passesto transmit the effort exerted on the load.loadWeight whose inertia exerts a force opposite to theforce exerted on the rope.PHYSICS: MECHANICS

27power sourceThe current leaves the battery by the negative terminal,flows through the circuit to power the lightbulbs andreturns to the battery by the positive terminal.switchMechanism allowing the current in anelectric circuit to be established orinterrupted.batteryDevice composed of one or moreinterrelated cells; each one accumulates areserve of electricity whose purpose is tosupply electricity to the circuit.cellsDevices that transform chemical energy into electricenergy in order to power electric devices (here, alightbulb).bulbGas sealed in a glass envelope into which the luminousbody of a lamp is inserted.shuntIt enables each device to have its own circuit and tofunction independently. This way, if one lightbulbdoes not function, the current continues to flow inthe rest of the circuit.nodeJunction point of two or more branches in the electric circuit.direction of electron flowElectrons move from the negative terminal toward thepositive terminal; this is opposite to the conventionaldirection of the current, which flows from the positivetoward the negative.positive terminalPolarity element of the battery toward which thecurrent flows through the circuit.negative terminalPolarity element of the battery from which the currentflows through the circuit.branchPart of the circuit between twoconsecutive nodes; it constitutes anindependent electric circuit.parallel electrical circuitIt is divided into independent branches, through which the current flows with partial intensity (in a series circuit,all the elements receive the same intensity).PHYSICS: ELECTRICITY AND MAGNETISM

28brushConductor that rubs against the commutator plates and transmits thecontinuous current produced by the dynamo to an exterior circuit.coilConductive wire that is rolled around thearmature cylinder, which rotates in themagnetic field produced by the inductor tocreate an electric current.armatureMoving part of the dynamo that is madeup of a coil, which produces an electriccurrent as it rotates inside the field.fan wheelDevice with blades that circulates air tocool the dynamo.frameMetal casing that houses the magnetic field.dynamoContinuous generator of electric current; it isused especially on bicycles for lighting.shaftCylindrical part that transmits arotational motion to the dynamo’sarmature.commutatorConductive plates that are insulatedfrom each other and connected to thefield coil; they collect and rectify theinduced alternating current.field electromagnetFixed electromagnet made up of an iron bar and coils; whenexposed to an excitation current, it creates a magnetic field.generatorsDevices that convert mechanical energy (here, a shaft’s rotational motion) into electric energy by moving a coilinside a magnet (electromagnetic induction).PHYSICS: ELECTRICITY AND MAGNETISM

29generatorsalternatorGenerator of alternating current that is usedespecially in the automobile industry(powering electrical devices) and in powerhouses.fan wheelDevice with blades that circulates air tocool the alternator.armature windingConductive wire on the armature; the rotormoves in front of it to produce an alternatingcurrent.claw-pole rotorMoving cylindrical part made up of a field winding between twopole shoes; it creates the rotating magnetic field required tooperate the alternator.armature coreFixed cylinder with a winding; the rotorturns within it to produce the electriccurrent.field windingConductive wire on the cylinderrotor; when exposed to an excitationcurrent, it creates a magnetic field.brushesConductive parts that rub against thecollector rings and transmit thecurrent produced by the alternator toan outside circuit.collector ringsInsulated conductor collars that areconnected to the coil of the field; theygather the induced alternating electriccurrent.drive pulleyMechanical unit integrated with theshaft; it is rotated by a belt that isconnected to an engine.shaftRod that is rotated by the pulley, which in turn causes the claw-polerotor to rotate.frameMetal casing that houses the magnetic field.PHYSICS: ELECTRICITY AND MAGNETISM

30dry cellsDevices that transform chemical energy into electric energy (direct current); they usually cannot be rechargedand the electrolyte is fixed in place.carbon-zinc cellBattery that produces 1.5 V (also calledLeclanché); its use is very widespread (pocketcalculators, portable radios, alarm clocks).negative terminalPolarity element of the battery toward which the current flows.bottom capLower metal cover; the negativeterminal is located at its center.zinc can (anode)Zinc receptacle that constitutes the battery’spositive electrode (anode).depolarizing mixMixture of carbon and manganese dioxidethat augments conductivity by acting as abarrier to polarization.carbon rod (cathode)Carbon rod set in the depolarizing mix; itconstitutes the battery’s negative electrode(cathode) collecting the electrons returningfrom the circuit.jacketBattery’s protective plastic casing.electrolytic separatorPorous paper combined with a chemicalpaste (ammonium chloride) that separatesthe two electrodes; this allows electrons topass, thus conducting electricity.top capUpper metal cover; the positive terminal islocated at its center.positive terminalPolarity element of the battery from whichthe current flows.sealing plugMaterial that seals the battery.washerDisk that compresses the depolarizing mix.PHYSICS: ELECTRICITY AND MAGNETISM

31dry cellssealing materialMaterial (nylon) that seals the battery.bottom capLower metal cover; the negative terminal is located at its center.sealing plugMaterial that seals the battery.manganese mix (cathode)Substance made up of manganese dioxide andcarbon; it constitutes the negative electrode(cathode).separatorPorous paper combined with a chemical paste(potassium hydroxide) that separates the twoelectrodes; this allows electrons to pass, thusconducting electricity.steel casingCovering that protects the battery.electron collectorZinc rod that is connected to the bottom cap; itcollects the electrons from the anode that areattracted to the cathode.zinc-electrolyte mix (anode)Substance that is made up of zinc and electrolyte(potassium hydroxide); it constitutes the positiveelectrode (anode).direction of electron flowWhen a chemical reaction occurs, the electrons move from thenegative terminal toward the positive terminal, thus creating anelectric current.alkaline manganese-zinc cellHigh-performance battery that produces 1.5 V and hasa longer life span than the carbon-zinc cell; it is usedin devices such as flashlights, portable CD playersand camera flash units.PHYSICS: ELECTRICITY AND MAGNETISM

32printed circuit boardUsually plastic insulated card with holescontaining electronic components; thecircuit is printed on its surface.printed circuitAll of the conductive metal bands on an insulated base (card), whichconnect a circuit’s components and allow a current to flow throughit.packaged integrated circuitElectric circuit under a plastic or ceramiccasing; it has pins for connecting it to thecircuit board.plastic film capacitorCommonly used component with twoconductive plates (aluminum, tin) separated byan insulator (plastic); it stores electric charge.ceramic capacitorComponent with two conductive plates (silver, copper) separated by an insulator (ceramic); itstores weak electric charge.electrolytic capacitorsPolarized components with two conductive components(aluminum, tantalum) separated by an insulator (electrolyte);they store strong electric charge.resistorsElectronic component that regulatesthe amount of current flowing in acircuit.electronicsThe scientific study of the behavior of the electron and its applications, such as computers, medicine andautomation.PHYSICS: ELECTRICITY AND MAGNETISM

33electronicspackaged integrated circuitIntegrated circuits are used especially in microprocessors, stereo equipment,calculators, watches and electronic games.connection pinMetal part that connects the integratedcircuit package with the metal bands ofthe printed circuit to which it issoldered.dual-in-line packageMost common type of package currently in use forintegrated circuits; it usually has between eight and48 pins, which are evenly distributed along each sideof the package.wireConductive element that connects the circuitcomponents to a connection pin.integrated circuitMiniature electronic circuit made up of a large number of components (such astransistors and capacitors); it is created on a semiconducting wafer usuallymade of silicon.lidCover that protects the integrated circuit in itspackage.PHYSICS: ELECTRICITY AND MAGNETISM

34repulsionForce by which two bodies pushagainst each other. Two poles of thesame orientation (both positive or bothnegative) repulse each other.north poleEnd of the magnet from which fieldlines originate and around which theexterior magnetic action is intense.magnetBody producing an exterior magneticfield; it attracts iron, nickel and cobaltas well as their alloys.field lineImaginary line representing thedirection of the magnetic forcesbetween the north and south poles.south poleEnd of the magnet to which the fieldlines are directed and around which theexterior magnetic action is intense.neutral lineLine separating the north and southlines of the magnet and exhibiting nomagnetic phenomena.magnetic fieldArea around the magnet wheremagnetic forces represented by lines offorce are exerted, resulting in electronmovement.attractionForce by which two bodies are pulledtoward each other; opposite polesattract each other.PHYSICS: ELECTRICITY AND MAGNETISMmagnetismAction exerted by magnets and magnetic fields and phenomena. Magnetism can be characterized by the forcesof attraction and repulsion between two masses.

amplitudeMaximum displacement of a wave inrelation to its mean position; itcorresponds to the amount of energytransmitted.troughLowest point of the wave.crestHighest point of the wave.displacementGap in relation to the mean position.wavelengthDistance between two consecutive crests or troughs; it correspondsto the distance traveled by the wave over time (its period).mean positionHorizontal line around which the waveoscillates, carrying energy.propagationMotion of a wave leaving its source.35waveOscillation caused by a disturbance; as it propagates through a medium (mechanical waves) or a vacuum(electromagnetic waves), it carries energy.PHYSICS: OPTICS

36radio wavesVery long electromagnetic waves (about1 meter) having low frequency; they are usedto transmit information (television, radio).microwavesVery short electromagnetic waves; their manyapplications include radar detection andmicrowave ovens.infrared radiationElectromagnetic waves emitted by warmobjects; their many uses includeheating, medicine, aerial photographyand weaponry.ultraviolet radiationElectromagnetic waves used especially to tanskin and in microscopy, medicine andlighting (fluorescent tubes).X-raysElectromagnetic waves used especially in radiology;frequent exposure can be harmful.gamma raysElectromagnetic waves of very high frequency thatare emitted by radioactive bodies; they are themost radiant and harmful rays and are usedespecially in treating cancer.visible lightElectromagnetic radiation that isperceived by the human eye andranges from red to violet.electromagnetic spectrumElectromagnetic waves that are classified in ascending order of energy (frequency); they propagate at the speedof light (300,000 km/s).PHYSICS: OPTICS

37PHYSICS: OPTICSblackcyangreenyellowredmagentablueredgreenbluecyanmagentawhiteyellowsubtractive color synthesisThe absorption of certain light rays (blue, green, red) bycolored filters (yellow, magenta, cyan) is used inindustries such as photography, film production andprinting to obtain intermediate tints.additive color synthesisThe superimposition of primary colors (blue, greenand red) is used especially in electronic screens(television, computer, video) to obtain intermediatetints.color synthesisTechnique of generating color by combining light rays or subtracting them to obtain a colored image.

38PHYSICS: OPTICSobjectLight rays emanating from an objectpass through the eye’s various mediato form an inverted image on the retina.focusPoint where light rays converge to forman image; the brain interprets the retina’supside-down image as right-side-up.corneaTransparent fibrous membrane extending thesclera and whose curved shape makes lightrays converge toward the inside of the eye.light rayLine along which light emanating from anobject propagates. The retina convertslight rays into nerve impulses, which arethen interpreted by the brain.normal visionThe image of an object is formed on the retinaafter passing through the lens, which, dependingon the distance of the object, expands or contractsto give a sharp image.lensTransparent elastic area of the eye; focuses images onthe retina to obtain clear vision.retinaInner membrane at the back of the eye covered inlight-sensitive nerve cells (photoreceptors); thesetransform light into an electrical impulse that iscarried to the optic nerve.visionAbility to perceive shapes, distances, motion and colors; it is related to light rays and varies depending on thedegree of sensitivity of the eye.

39PHYSICS: OPTICSastigmatismUsually caused by a curvature of thecornea, it is manifested by blurred visionwhen viewing both near and far objects,depending on various axes.myopiaThe image of a distant object is formed infront of the retina due to a defect in the lightrays’ convergence. This makes distantobjects hard to see.hyperopiaThe image of an object is formed behind theretina due to a defect in the light rays’convergence as they pass through the lens. Thismakes near objects hard to see.visionvision defectsImages do not form on the retina, thus resulting inblurry vision; such defects are corrected byeyeglasses, contact lenses or even surgery.focusPoint where light rays converge to form animage; the brain interprets the retina’s upside-down image as right-side-up.focusPoint where light rays converge to form animage; the brain interprets the retina’s upside-down image as right-side-up.focusPoint where light rays converge to form animage; the brain interprets the retina’supside-down image as right-side-up.convex lensCorrects hyperopia by causing light raysemanating from an object to converge andproject an image onto the focus of the retina.concave lensCorrects myopia by causing light rays emanatingfrom an object to diverge and project an imageonto the focus of the retina.toric lensHas various powers depending on the rays’ axes ofconvergence; it is used to offset the visualdistortion caused by the cornea.

40PHYSICS: OPTICSconverging lensesThicker in the center than on the edges;they cause parallel light rays emanatingfrom an object to converge onto the samepoint.convex lensLens with one side bulging outward; the greater the bulge, themore the light rays converge.biconvex lensLens with both faces bulging outward.positive meniscusLens where the concave side (curvinginward) is less pronounced than theconvex side (bulging outward).negative meniscusLens where the concave side (curvinginward) is more pronounced than theconvex side (bulging outward).diverging lensesThicker on the edges than in the center; they causeparallel light rays emanating from an object to diverge.biconcave lensLens with both sides curving inward.concave lensLens with one side curving inward; the greater thecurvature, the more the light rays diverge.plano-concave lensLens with one flat side and one concave side (curving inward).plano-convex lensLens with one flat side and one convex side (bulging outward).lensesTransparent pieces of material (usually glass) that cause light rays to converge or diverge to form a sharp image(eyeglasses, microscopes, telescopes, cameras).

41pulsed ruby laserDevice that produces a thin and very intense colored light beam; its various applications include fiber optics,manufacturing and surgery.ruby cylinderRuby bar (crystallized alumina) that containschromium atoms. It has mirrors at each end,which form the amplification medium toproduce the laser beam.photonEnergy particle that emits the ruby-chromium atoms as they are excited byflashes in the tube.partially reflecting mirrorIts partial transparency allows lightbeams to escape.flash tubeLamp that acts as an energy source by emitting a flash of whitelight, which excites the ruby atoms and causes them to emitphotons.reflecting cylinderLaser’s metal casing whose inside ispolished so that it reflects the lighttoward the ruby cylinder.fully reflecting mirrorReflects all the light energy toward the partially reflecting mirror. Thereflection between the mirrors intensifies the light to form a highlyconcentrated beam.cooling cylinderCasing in which water generally circulatesto cool the ruby cylinder, which becomesvery hot as it produces the beam.laser beamStraight and powerful monochromelight beam that is emitted by thedevice.PHYSICS: OPTICS

42PHYSICS: OPTICSprism binocularsOptical instrument made up of two identical telescopes, one for each eye; it magnifies both near and distant objects.bridgePart of the frame joining the two telescopes.eyepieceOptical disk or system of disks through which theeye sees the image produced by the lens.lens systemOptical system made up of a set of lenses throughwhich light passes to transmit a magnified imageof an object to the eye.Porro prismDual-prism system (blocks of glass at rightangles) found in most binoculars; it diverts thelight rays toward the eyepiece to correct theinverted image formed in the objective lens.hingeMechanism for adjusting the distancebetween the eyepieces to the user’seyes.central focusing wheelFocusing ring for both the objective lenses; it isused to manually adjust the sharpness of the image.focusing ringRing on each eyepiece for manuallycorrecting for the difference between theuser’s eyes.bodyCylindrical body of the binoculars thathouses the optical system and throughwhich the light rays pass.objective lensLens that captures the light from the observedobject and causes it to converge to form amagnified inverted image.

43microscopeOptical instrument that consists of a system of lensesdesigned for observing organisms that are very small orinvisible to the naked eye by magnifying their images.eyepieceSystem of lenses that acts as a magnifier; the eye looks through itto see an enlarged image of the image produced by the objective.revolving nosepieceRotating plate to which objectives of different powersare fixed to allow them to be used in successionduring a study.objectiveLens system that captures the lightfrom an observed object and makes itconverge to form an enlarged invertedimage.stage clipSpringlike metal blade that keeps theglass slide on the stage.glass slideFine glass plate on which the object tobe studied is placed.stageMetal plate with an opening in themiddle; the glass slide and thecomponents keeping it in place areplaced on it.condenserOptical system that is usually made upof two lenses, which concentrate thelight reflected by the mirror onto theobject under study.mirrorPolished glass surface that reflects the surrounding lightonto the object under study to illuminate it.baseSupport that stabilizes the microscope.armVertical part of the microscope thatsupports the components (draw tube,stage) and contains the focusingmechanisms.magnifying glass and microscopesOptical instruments used to magnify the image of a near object; they range in strength from low (magnifying glass) to strong (microscope).PHYSICS: OPTICS

condenserOptical system that usually has twolenses to concentrate the light emittedfrom the lamp onto the object understudy.44binocular microscopeIts two eyepieces allow both eyes tobe fully applied; this provides adegree of depth to the image andprevents eyestrain.draw tubeOne of two cylindrical tubes that housethe eyepieces; it is often made up oftwo converging lenses.eyepieceSystem of lenses that acts as amagnifier; the eye looks through it tosee an enlarged image of the imageproduced by the objective.limb topUpper part of the arm that supports therevolving nosepiece.objectiveLens system that captures the light fromthe observed object and makes itconverge to form an enlarged invertedimage.stage clipSpringlike metal blade that keeps theglass slide on the stage.glass slideFine glass plate on which the object to bestudied is placed.field lens adjustmentDevice with a variable-diameteropening that adjusts the amount oflight illuminating the object.condenser adjustment knobScrew that centers the condenser’s light beam in the field of vision by moving italong a horizontal plane.baseSupport that stabilizes the microscope.lampElectric device that produces a lightbeam to illuminate the object understudy.revolving nosepieceRotating plate to which objectives ofdifferent powers are fixed to allow themto be used in succession during astudy.magnifying glass and microscopesPHYSICS: OPTICS

45condenser height adjustmentScrew for raising and lowering the condenser.mechanical stage controlDevice for raising and lowering the mechanical stage.fine adjustment knobHigh-precision focusing device for adjusting the distance between the objective andthe object under study.stageMetal plate with an opening in the middle; the glass slide and the componentskeeping it in place are placed on it.mechanical stageAdjustable part with two guiding screws that moves an object from right to left andfrom front to back on the stage.armVertical part of the microscope that supports the components (draw tube,stage) and contains the focusing mechanisms.body tubeMetal casing that houses the microscope’s two eyepieces and through which light rays pass.coarse adjustment knobMedium-precision focusing device for adjusting the distance between the objectiveand the object under study.magnifying glass and microscopesPHYSICS: OPTICS

46cross section of an electron microscopeElectron microscope: it uses an electron beam (as opposed to light) to provide magnification that is markedlysuperior to that of an optical microscope.electron beamSet of negatively charged particles that propagate towardthe specimen.electron beam positioningControl that positions the electron beam along the opticalaxis so that it reaches the specimen.beam diameter reductionThe two lenses of the condenser cause the divergentelectron beam emitted by the gun to converge.focusing lensesSystem of magnetic lenses (electromagnets) thatconcentrate the electron beam on one spot onthe specimen.visual transmissionThe electron beam explores the surface of thespecimen, which in turn emits electrons to forma point-by-point image on the screen.vacuum chamberPart of the microscope in which pressure can bereduced so that the electrons can move.electron gunDevice that usually consists of a tungstenfilament that is heated to produce an intenseelectron beam, which illuminates the specimen.vacuum manifoldConduit connected to a pump that createsenough of a vacuum in the microscope that it canfunction.condenserSystem of magnetic lenses (electromagnetsproducing a magnetic field when excited by anelectric current) that concentrates the beam ontothe specimen under study.aperture changerDevice that adjusts the diaphragm opening inorder to change the diameter of the beam.aperture diaphragmDevice with an opening whose diametercan be changed to narrow or widen thediameter of the electron beam.stageAdjustable metal plate (stage) on whichthe specimen is mounted in order to studyit.magnifying glass and microscopesPHYSICS: OPTICS

control visual displayScreen that displays the image of the specimen enlargedand in relief (as a result of a surface scan by the beam),as well as data on the microscope’s operations.47electron microscope elementselectron gunDevice that usually consists of a tungstenfilament that is heated to produce anintense electron beam, which illuminatesthe specimen.liquid nitrogen tankReservoir containing nitrogen to cool thespectrometer.specimen chamberPart of the microscope in which a specimen isplaced for observation.vacuum system consoleCompartment housing the vacuum system.specimen positioning controlButtons for precisely lining up a specimen in relation to theaxis of the electron beam.control panelConsole containing buttons foroperating the microscope.photographic chamberPhotographic device that prints animage of the specimen onto a sensitivesurface.data record systemInstrument for saving data pertaining to themicroscopic analysis onto media such asvideocassette and DVD.spectrometerInstrument for determining thechemical composition of a specimen.magnifying glass and microscopesPHYSICS: OPTICS

48telescopic sightOptical instrument mounted on a rifle or a measuring device to increase accuracy.main scope tubeCylindrical body of the telescopic sight that houses the optical system and through whichthe light travels.objective lensLens that captures the light from theobserved object and causes it to convergeto form a magnified inverted image.PHYSICS: OPTICSconvex lensLens with one side bulging outward; the greater the bulge, the more the light raysconverge.magnifying glassConverging lens that magnifies the image of an object.handlemagnifying glass and microscopes